Previous reports from this and other laboratories have shown that the
histological changes in the femoral head that are associated with steroid
treatment are consistent with avascular necrosis of the femoral head. In
this experiment, we studied the effect of core decompression on femoral
head blood flow in steroid-treated rabbits using the microsphere technique.
The results showed that there was a gradual decline of femoral head blood
flow in animals that received weekly injections of methylprednisolone
without core decompression. The femoral head blood flow in animals that
underwent core decompression after six weeks of steroid treatment showed a
gradual normalization within four weeks after core decompression.